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    <title>Document</title>
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    <script>
        /*
            问题: 在js调用函数时传递变量参数时，是值传递还是引用传递
            答案: 
                理解1: 都是值(基本/地址值)传递
                理解2: 可能是值传递，也可能是引用传递(地址值)
        */
        let a = 3;
        function fn(a) {
            a = a + 1;
        }
        fn(a);
        console.log(a);//3
    </script>
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